The Patient Protection and Affordable Care Act creates a hospital readmission reduction program to help acute care hospitals decrease avoidable rehospitalizations. Research suggests approximately twenty percent of all Medicare patients are rehospitalized within 30 days of discharge from acute care and that the majority of these rehospitalizations are preventable. Research examining rehospitalization has focused primarily on patients discharged from acute care hospitals. We will examine rates and reasons for hospital readmission in high volume and high cost patients, such as those with stroke or hip fracture, who receive inpatient medical rehabilitation. This is an understudied population with important implications for health care resources and costs as the U.S. population continues to age. Our goal is to determine rates and factors associated with hospital readmissions in persons receiving inpatient rehabilitation services for the six largest rehabilitation impairment groups as defined by the Centers for Medicare and Medicaid Services (CMS). We propose the following Specific Aims: Aim 1. Examine national data from the Centers for Medicare and Medicaid Services and the Uniform Data System for Medical Rehabilitation (UDSMR) to determine rates of hospital readmission for the six largest impairment groups receiving inpatient medical rehabilitation in the U.S. (stroke, fracture of the lower extremity, joint replacement of the lowe extremity, debility, neurological disorders and traumatic brain injury) (MedPAC, 2011). Aim 2. Determine patient characteristics (sociodemographic and clinical/functional) associated with hospital readmission across the six impairment groups (see Aim 1). We will examine data from the Centers for Medicare and Medicaid Services files and the Uniform Data System for Medical Rehabilitation dataset for the years 2006 - 2010 (~ 1.3 million patient records). We will use exploratory data analysis and descriptive statistics to determine the rate of hospital readmission for the six rehabilitation impairment categories. Time-to-event survival analyses will be used to examine personal and clinical factors associated with hospital readmission during the first 90 days after discharge. Our interdisciplinary research team has twenty years of experience using large national datasets to study rehabilitation outcomes. The findings will address priorities of the Affordable Care Act, provide information useful in developing future predictive models, and assist in documenting hospital accountability and establishing quality indicators.